I am trying to do something a little bit specific, and I can't seem to find if it is even possible. So I thought I would lay down the question here.
What I'm looking for is a way to change the anchor point of the scrollviewer from the top to the bottom (however you look at it). I'll explain what I mean.
By default when the control contained in your scrollviewer gets taller, so will your vertical scrollbar scollableheight.
But what happens is, the vertical scrollbar will stay at the same scrolloffset from the top, while what I want is that the vertical scrollbar keeps it's position relative to the bottom. The reason I want this behaviour is because I am creating a list that the user can expand more of by scrolling to the top. but then when I add the new items it looks like the scrollviewer scrolls up to the newly added items. (although it is actually the content the is pushed down) So if the scrollviewer would have the vertical scrollbar anchored to the bottom, the visible part of the content would stays at the same position to the user because the distance from that part to the bottom didn't change.
I hope you can understand what I'm trying to do.
I allready found one way of doing this, but it is not the desired option to me.
Option 1) Apply a Scaletransform of -1 in the Y-axis to the scrollviewer to flip it upside down. Then apply another ScaleTransform of -1 in the Y-axis to the content of the scrollviewer to make the content right side up.
But the problem with this technique is that for one, when you scroll using your mousewheel the scrollviewer scrolls inverted as normal. And second, I'm using 2 scaletransformations just to change the behaviour of the scrollviewer, and not even for eye candy. So that seems a bit excessive to me.
Option 2) anyone?
Related
I have two GroupBoxes on the left side of one of my TabControls, call them GroupBox A (top left), and GroupBox B (bottom left). The GroupBoxes do not resize like I would hope.
Example:
When I resize the main form that has the TabControls with my mouse, or maximize it, or move it to a screen with lower resolution, GroupBox B keeps its width / height. This causes GroupBox B to draw over GroupBox A, kind of like a 'always on top' effect.
Desired:
Would like both GroupBoxes to resize according to one another / proporitionally and fit the area they are given.
Ideas?
A tableLayoutPanel can help with this.
Add a tableLayoutPanel and size it to fit your needs.
Anchor the table to Top, Bottom, Left, and Right
Put GroupBoxA into the upper left cell of the table
Put GroupBoxB into the lower right cell of the table
For both GroupBox size them accordingly and anchor them to all 4 sides.
Now they will grow and shrink proportionately with the app.
Additionally you can add more of your controls to the table. If you need a control to span multiple rows or columns use the RowSpan/ColumnSpan property.
If your GroupBox is inside another control like a tab or something, then do as below:
In my case I had a GroupBox inside a tab and I called the below methods in the InitializeComponent() method to force the Groupbox to adjust to the tab size.
this.groupBox4.ResumeLayout(false);
this.groupBox4.PerformLayout();
this.tabPage2.ResumeLayout(false);
this.tabPage2.PerformLayout();
And If you have multiple GroupBoxes, you need set the anchoring accordingly.
I faced a similar problem, I just had used the split container for both GroupBoxes, anchored the split container at top, bottom, left an right of my main form, and both GroupBoxes too, at top, bottom, left and right of their containers.
Slightly off topic from the original question, but my issue was that my MaximumSize field of my Group Box was not set, or was too small so I could not resize the height!
Altought the question is pretty old, someone might still find it useful...
I had the same problem and found a working solution -> instead of changing the width/height of the GroupBox, change its minimum width/height in the Form's resize method
edit: fixed typo
private void Form1_Resize(object sender, EventArgs e) {
groupBox1.MinimumSize = new Size(this.Width /2, this.Height);
}
I've got a Silverlight user control that contains a datagrid. The datagrid is bound to an ObservableCollection. The user control is displayed in a popup window that I show in response to some event in another control
There are about 80 objects in the collection, and I've set a fixed height of 400 on the datagrid, so only about 20 items can be shown at one time, and the vertical scrollbar should be shown, with a thumb size occupying about 1/4th of the control height.
However, what's actually happening is that the scrollbar occupies almost the whole control height; maybe 95% of it. The datagrid displays the first 20 items. When I click on the scrollbar down arrow, the scrollbar moves down a little to occupy the bottom 95% of the scroll area, and the datagrid displays the last 20 items.
It gets weirder. If I move over the items in the grid and scroll down using the mouse wheel, then the items scroll correctly and I can view the whole list, although the scrollbar remains the same size.
And then, if I close the popup and reopen it, the scrollbar now appears with the correct height and it works correctly.
Finally, if I just show the control directly on the page, and not in a popup, it works fine.
What's going on here?! Has anyone else run into this problem? Help!
Update: The problem seems to be the way that I'm showing the popup. For various reasons, I had to implement the popup display in a somewhat tricky way, and it's this that's causing the trouble.
I recoded this, removing some crufty stuff, and the problem went away; see my update. This isn't really a solution as such, but I wanted to close out the question for the record.
I have a StackPanel inside of a ScrollViewer.
I have a slider that does a scale transform on the stackpanel to allow zoom-in and zoom-out functionality. The problem is that when I zoom in, the scrollviewer doesn't treat the content as being 'bigger'.
So, if I scroll in a little and scroll as far right as I can go - it stops me before I get to the end of the content. If I zoom back out to the untransformed level, I see that it's stopping exactly at that point. If I zoom in a lot, I can only see a small fraction of my total content when I scroll all the way over.
I can change the TransformOrigin to control which side loses the most content; but I figure there should be some way for the scrollviewer (or another control?) to take care of it for me.
Are you doing render transform, or layout transform? You should be doing the latter.
I'm trying to modify the default graph viewer of the Graph# library because its user interface is awful (just try dragging a node outside of the boundaries, you'll see!)
The basic setup is this: there is a GraphCanvas control (inherited from Panel) which has children of Vertex and Edge control types. What I want to achieve is:
GraphCanvas has scroll bars if the contents do not fit in the screen;
GraphCanvas can also be scrolled by "dragging" it (just click on an empty space and drag);
GraphCanvas can be zoomed in and out (via CTRL+mouse wheel);
Vertices can be dragged around. If a vertex is dragged outside the current boundaries of GraphCanvas, the boundaries are increased. The scroll bars should reflect this, however the current viewport should not scroll away while the vertex is being dragged . The same goes if dragging a vertex reduces the boundaries of GraphCanvas - it should stay the same size until the drag operation is finished and resize only then. Automatically scrolling the viewport during a drag operation is awfully confusing and easily introduces dragging errors. See the original implementation if you want to know what I mean.
Although I've got a fair bit of experience with .NET, I'm still a complete beginner in WPF. My current attempt is (in the measure/arrange layout phase) to give each vertext the XY coordinate it desires (even if negative) and implement zooming/scrolling by handling mouse events on the GraphCanvas and modifying the RenderTransform property. Dragging just changes the XY coordinates on the specific vertex (probably triggering the re-layout of the whole thing which would be nice to avoid too). Scrollbars are implemented by placing the GraphCanvas inside a ScrollViewer and implementing IScrollInfo on the GraphCanvas.
Unfortunately there seems to be a problem: I can get mouse events on the GraphCanvas itself only if it has a background at the point. That would be OK, I want a white background anyway, but in the negative coordinates of the GraphCanvas it does not draw the background - and thus does not respond to mouse events.
I'm also wondering if I'm doing the Right Thing by allowing all my child controls (vertices and edges) to go into negative coordinates. How would you implement this?
Added: To clarify about the background problem check out the following screenshot:
(source: valts.21.lv)
What you see here is a simple Windows Forms form with a WPF Host control on it. That has a ScrollViewer in it, and the ScrollViewer has the GraphCanvas in it. The GraphCanvas contains 4 vertices and 6 edges.
The GraphCanvas is stretched to fill the ScrollViewer. But since some of the vertices are at negative coordinates, it has a RenderTransform applied which simply shifts everything to the right (TranslateTransform). It also has a white background brush.
Note the gray area on the left. That's still a part of the GraphCanvas, but the background brush somehow doesn't exted there. Also, if I left-click there with my mouse (not on a node, but on the gray area), I do NOT get an event. If I left-click on the white area, I get all events just fine.
Call CaptureMouse on canvas.mouseDown and ReleaseMouseCapture on mouse up. Also, if you set your canvas background to transparent it will still be hit testable
You can attach a 'Draggable' behavior to each element.
I am new to WPF and the ScrollViewer is frustrating me. Either I just don't "get" it, or it is a limited control.
Here are my Frustrations:
Bad Horizontal Scrolling The horizontal scroll bar is only visible at the bottom of the list (I have to scroll to the bottom to see it)
Bad Borders I have a ListBox in my ScrollViewer. When I start the bottom of the list has no border and when I scroll down, the top border (line) of the list box disappears. I can kind of understand this, but attempts to set BorderThickness or BorderBrush for the ScrollViewer result in no change (I wanted to use the ScrollViewer's border to keep a constatant box around the list contents, like most list boxes out in cyber world).
Bad Handling of Short Lists When the items in the list don't reach the bottom the ScrollViewer keeps the scroll bar there and just dithers it out. Why not free up some space and remove it?
Some of these may seem petty (and they are). But users expect a certain look and feel from their apps and WPF is making it hard to get this out of the box.
If you know a way to fix any of these I would love a response. If there is a better way to deal with scrolling than using the ScrollViewer that would aslo be welcome.
Maybe you see some scroll bar from inside the list rather than the scroll bar from the ScrollViewer? Try setting <ScrollViewer ... HorizontalScrollBarVisibility="Auto"> (default is Hidden, which means that no horizontal scroll bar is shown ever; also try "Visible" for the sake of debugging)
Is putting a <Border> around the ScrollViewer an option?
VerticalScrollBarVisibility has a default value of Visible. If you want the scroll bar to disappear when it is not necessary, try <ScrollViewer ... VerticalScrollBarVisibility="Auto">.